On the same subject I've found very useful "The Little Manual of API Design" by Trolltech (the makers of Qt): http://chaos.troll.no/~shausman/api-design/api-des

On the same subject I've found very useful "The Little Manual of API Design" by Trolltech (the makers of Qt): http://chaos.troll.no/~shausman/api-design/api-design.pdf http://chaos.troll.no/~shausman/api-design/api-design.pdf The documents start stating some characteristics of Good APIs: 1. Easy to learn and memorize 2. Leads to readable code 3. Hard to misuse 4. Easy to extend 5. Complete